TopGroove™ Hardware TopGroove Toolholders and Boring Bars clamp screw clamp shim screw insert shim insert size and style clamp clamp screw shim shim screw NG-1L CM-109 S-304 — — NG-2R CM-182 S-310 — — NG-2L CM-183 S-310 — — NG-2R CM-74 S-310 — — NG-2L CM-75 S-310 — — NG-3R CM-184 S-412 — — NG-3L CM-185 S-412 — — NG-3R CM-72 S-412 — — NG-3L CM-73 S-412 — — NG-3R* CM-78 S-412 — — NG-3L* CM-70 S-412 — — NG-4R CM-72 S-412 SM-420 SL-344 NG-4L CM-73 S-412 SM-420 SL-344 NG-5R CM-80 S-352 — — NG-5L CM-81 S-352 — — NG-6R CM-120 S-412 SM-416 S-111 NG-6L CM-121 S-412 SM-416 S-111 TopGroove relief grooving NU-3125R CM-72 S-412 — — NU-3125L CM-73 S-412 — — NU-3125R** CM-72 S-618 — — NU-3125L** CM-73 S-618 — — Utility threading NTU-4R CM-72 S-412 — — NTU-4L CM-73 S-412 — — *25mm diameter boring head. **Boring head. E84 widia.com